Air control instrument



Sept. 12,1944. MOORE 7 2,358,242

AIR CONTROL INSTRUMENT Filed Jan. 3. 1940 FIG. I.

GAS

20 semw'on INVENTOR couzmm a oon:

I ATTORNEY Patented Sept. 12,

T OFFICE AIR CONTROL INSTRUMENT Coleman B. Moore, Carroll Park, Pa., asslgnor to The Brown Instrument Company, Philadelphla, Pa... a corporation oi Pennsylvania Application January 3, 1940, Serial No. 812,303

3 Claims. (Cl. '137-140) The present invention relates to air control instruments that may be used to set up a controlling pressure proportional to the value of a variable condition or totheratio between the values of a' plurality of conditions. Instruments of this type may be used to control the value of any measurable condition such as temperature, pressure or flow-in response to varia- I tions in similar or related conditions.

For purposes of illustration the invention is described in connection with a tubular oil still in which it is desired to control the rateof cracking.. In such a still oil is forced under pressure through the tubes of the still and is heated to a high temperature. This cracks the oil or changes it from heavy to light hydrocarbons and the amount of the latter that are produced has a bearing on the efllciency of the still. In order to control the process the amount of heat supplied to the still is varied in response to the rate at which the oil is cracked. This is determined by taking a sample of the liquid and.

vapor in the line leaving the still and separating the liquid from the gas. The ratio of the volumes of these constituent quantities is then used to vary the fuel supplied to the still.

The instrument of my invention is used in connection with meters measuring the flow of any' suitable'flow controller 5 that is responsive to the diflerential pressure in an orifice 6 located in the supply line i. The temperature of the oil in the exit pipe I is measured by a temperature controller 8 of suitable type that is used to adjust the opening of a valve 9 in a fuel supply line III. This controller may be omitted from the system, if desired, as willbe. later described.

-As the oil in the tubes 2 is heated it tends to break down into lighter hydrocarbons, some of which are in liquid and some of which are in gaseous'form. In order to perform the subsequent operations on the oil economically and at the same time produce the highest possible yield of the' desired product it is determined by test what the best ratio between the gas and liquid is for the oil being u'sed. This ratio may be portion of the product. This sample passes gas and liquid from the samplingline to set up a control pressure responsive to the ratio thereof, which pressure is used to tion of heat to the still.

Thevarious features of novelty which characterize my invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, however, its adyantages and specific objects obtained' 'with'its use, reference should be had to the accompany- .ing drawing and descriptive matter in which -I have illustrated and described a preferred'embodiment of the invention.

In the drawing:

Fig; 1 is a diagrammatic view of the various components of the control system;

e Fig. 2 is a view of one form which the in strument may take; and w Fig. 3is a viewtaken' on line 3-3 of Fig. 2,.

Referring to Fig. i there is shown an oil still i of conventional form in which are located convolutions of a tube 2 through which oil to be treated is forced under suitable pressure. A

vary the applica-' regulating valve 3 is located in the oil supply pipe 4. This valve is adjusted to insure'the through a cooler I! that is supplied with somecooling medium such aswater. through inlet and outlet pipes i3 and i4, respectively. As

the sample leaves the cooler it goes to a gas separator it in which the liquid and gas are separated before they are measured. In order to take care of the varying rates of evaporation that will take place in the gas separator if the sample is discharged into it at different temperatures, a valve i8 is placed in the outlet line it for the cooling fluid in the cooler i2. This valve is adjusted by a suitable temperature controller I! that is responsive to the temperature in the separator It. The gas leaving the separator i5 passes through a line it; having a pressure regulator is in it, to a gas volume measuring meter 20. The liquid leaving the separator l6 passes through a line 2| to a liquid volume is provided with ashait I3 and the meter 22 i8 provided with a shaft 24; each of which rotate at aspeed proportional to the volume of the fluid being measured. The gas and liquid discharged from the meters 20 and 22 may either be returned to the system or discharged to the atmosphere'.

The relative speeds of rotation shafts 23' and II are used with an instrument 25 to create an air pressure proportional to the ratio of the a It.

3; and liquid. This air pressure is applied through a line 26 in either one of 'two ways. depending upon the use of the instrument I. Ifthecontrolof thetueltothestill l istobe in response to temperature, as above described, a valve 21 will be kept closed and the pressure inlineiiwillbeusedtoresetorchangethe control point of the instrument I in accordance with the rate of cracking. This means that the value at which the controller 8 maintains the exit temperature of the oil in line I will be changed as the ratiobetween the gas and liquid in that line changes. If, on the other hand, the instrument 8 is to be used solely as a recorder to keep a record of the exit temperature of the oil, the instrument will have no control motion. In such a case valve 21 will be open and a valve 28, in the line leading to instrument 8, will be closed so that the pressure in line I will'be applied directly to the valve 9. In this case .the temperature in the still is being controlled directly in response to the rate of cracking.

2,sse,242

"Contractionofthebellowsisopposedbyaspring One form of mechanism by which the pressure in line 26 can be made proportional to the ratio of the speeds of shafts 23 and II, or the relative volumes ofgas and liquid obtained from the still i is shown in Fig. 2. In order to accomplish this the shafts 23 and 24 are extended into the casing of instrument 25 in any suitable or convenient manner. The rotation of these shafts may also be reduced or increased to suitable speeds by means of any well known form of gearing. The mechanism now to be described is located in the casing 25.

Referring to Fig. 2, there is shown a bracket 60 that may be attached in any suitable manner to the casing of instrument 25. Journalled for rotation in this bracket is a hollow sleeve I having an elongated pinion 62. formed on it, which pinion and sleeve are normally biased upwardly by a spring 83. The pinion is continuously rotated by a gear 64 on the end of shaft 24 that is rotated at a speed proportional to the volume of liquid in the sample taken from the exit pipe I of the still I. Rotatably mounted in the upper end of the sleeve OI is a valve that takes the form of short shaft]! having a flat surface on one side I. The left endv of lever ll has pivoted to it a thrust link ll having a socket formed inits lower end which receives a pivot bearing formed on the uppersurface of disc it. a

Assume, for example, the rotation of shafts 23 andiltobein such adirectionthattheshaft I! and sleeve ii lung. 8 are both rotating counter-clockwise. Therefore, if the speed of ii is increasedrelativetoiltheopeninglcwillbe closedoil',increasingthepressureinline 69 and chamber ll. Thisincrease inpressurewill collapse bellows ll and, throuehconnection I8, move the lever 11 counter-clockwise. Such movement will'force link l0, disc ti, and sleeve Oi downwardly against the force of spring Q3 to move disc 66 outwardly along disc 81. The disc 86 will, therefore, be rotated faster so that its speed will equal that of sleeve ii. In this manner a state of equilibrium will be reached with the pressure in the system higher than it previously was. The

same operation would take place if shaft 23 and 1 thereby shaft 65, were slowed down with respect toshaft 2i andsleevetl.

If the relative speeds of shafts 28 and I4 changed in the opposite manner opening III would have been given a larger effective opening to permit more air to escape therethrough. This would reduce the pressure in the system and permit bellows 14 to expand under the action-of spring I9. Sleeve 8|, disc 68 and lever 11 will thereby be moved under the action of spring 63 to move disc 66 toward the center of disc 81 to slow down the former. The system will then reach a position of equilibrium with a lower pressure than before.

The pipe is connected to the pipe 28 so that the pressure changes produced therein by the relativespeeds-of shafts" and 2| can be applied to either change the control point of instrument 8 or act directly to adjust valve 9; Movement "of -leverllmaybeusedtoadjustapenintheinstrumentiibymeansofalinkil and anycon-.

as shown in Fig. 3. This shaft is. formed integral with a driven disc 68 by which it is driven independently of the sleeve II at varying speeds from, a driving disc or attached to the shaft ll. The

,disc :1 is, therefore. driven at a speed mo r.-

. tional to the volume of sis flowing through the meter 2|, and may in turn drive the disc Nata speed proportionalto therradial distance of the latterfronithecenterofdiscil. r

Air under suitable pressure'is supplied past a restriction 88 in a pipe '9 to the sleeve 8| through which it to escape by way of a bleed opening ll formedinthesleeve. Ifthesleevell and shaftllarerotatingat-thesamespeedtheeseape ofairthroughtheopening ll-willbs constant.

theirspeedthesleeveiiandshaftilwillbe rotated relative to each other to vary the effective si'seofopening'llltopermitmoreorless'sirto escape therethrough.

sure in pipe and in achamber II that is in communicatimi-thercwith by means of'a branch pipe II.

The chamber." a soup l8 and a bellows u that are attached at their-M GI to a stationary bracket". Pivotedcnthcbracketatlika formedbythespacebetween ventionallinkageuponwhichsaidpenmaybe In the above description it has been assumed that botha gas meter and a liquid meter were for the proper operation of the system. In somecases, however, it may be necessary to have only'one meter or the other. If this is so the instrument of my invention is equally as applicable toset npa pressure proportional to the rbtativespeedofoneshaftssitisoftwo. In osdertodothmhowevenoneofthepartsthat isrotated byeither shaft 23 or 24 must berotated ataconstantreferencespeed.

Ifit-isdcsired,theshaft flmaybedrivenat -aconstant orreferencespeed. Thenif theshaft 2| was connected to either meter shaft 23 or meter shaft 24 a pressure would be produced by the instrument that is proportional to the speed When. however, either of shafts 28 or 2! change of theshaftnsedwithrespecttoaconstant. "Ihis pressure would then be applied to adiust valve I. in accordance with either the'volume of gas oroilasthecasemaybe.

Bythouseofmyinstmmenttheheatsupplied tothestilllmaybesoadiustedthattheresultingproducthssthedesiredproportionsofgas andliqnid. Anydeviationtherefromwilieause anincresseordecreaseinheatsnppliedtoreturn -theratioofthegasandliquidproducedtoits I l nu lu Whihm'withtheprovisions of the lever thathaspivotaflyattachedat one end-1s mfbavsillustratedsnddescribedthebest form of my invention now known to me, it will be apparent to those skilled in-the art that changes may be made in the form of the apparatus disclosed .without departing from the spirit of my invention as set forth in the appended claims,

4 and thatin some cases certain features of my invention may sometimes be used to advantage without a corresponding use of other features.

Having now described my invention, what I claim as new and desire to secure by Letters Patent isf 1. In an air control instrument the'combination with a first member driven at a constant speed, a valve member, means to drive said valve member at varying speeds from said first member, a second member driven at a variable speed proportional to the value of a condition, a port in said second member cooperating with said valve member, a supply of air under pressure adjusted by relative movement of said valve member and port, and means to adjust the speed of said valve member in response to variations in the air pressure. i

2. In an air control instrument, the combination of a shaft rotated at speeds proportional to the value of a variable condition, a second shaft rotatable at speeds proportional to the value of a second condition, an air conduit, means to supply air to said conduit from a substantially constant pressure source, a valve member, a bleed port member connected to said conduit, said members cooperating to regulate said pressure supply, means to drive one of said valve and port ,members from the first shaft, means to drive the other of said valve and port members from the second shaft, whereby it they are not rotated at the same speeds their relation will change to vary the bleed of air through said port and therefore the pressure in said conduit, and means responsive to variations in pressure in said conduit to equalize the speeds of said valve and port members.

3. In an air control-instrument the combina-- 

